The Homeshell installation is constructed using Insulshell (developed by Sheffield Insulated Group and Cox Bench ), which is a flexible, quick, low-cost and highly energy efficient building system which can help contribute to solving the UK’s current housing crisis. This installation will be a three and half storey building, arriving as flat-pack panels on one truck and will take only 24 hours to construct on site.
Insushell appears to be a new form of structural insulated panel with a patented joint system, a 60 minute fire rating and an insulating value of U0.16 for 239 mm panel, which translates through a complex calculation to R35 for an 8" thick panel.
(Where in North America we use R values for walls, which get higher as the insulation gets better, Europeans use U values, which measures the amount of energy in Watts that gets through the wall, so the lower the better. North American window manufacturers use U values, I think to hide how badly their windows actually perform)
The structure is similar to balloon framing, where the exterior structure goes from foundation to roof; floors are "simply lowered into position and fitted to a bespoke [custom] locking ledge which again is designed to provide high levels of thermal and acoustic insulation." This differs from traditional platform construction, where the floors sit on a wall and then the next wall sits on the floor, allowing many places for air to leak and insulation to be screwed up during installation; It wraps the house in a complete envelope of insulation. The panels can be manufactured as large as 14'-6" wide by 78 feet long, although the delivery of a panel that size would be interesting to watch. The architects write:
The Insulshell system is so flexible that it can be used for many building types from homes, apartments, schools to factories and health centres. Even the Velodrome at London 2012 was constructed using this method. It offers many advantages over traditional building techniques. It can be adapted to suit any location and it is great for difficult, highly urban or small sites.
Ivan Harbour, Senior Partner at Rogers Stirk Harbour + Partners says:
“The Homeshell delivers generous space, exceptional insulation, daylight and acoustics. We believe it holds many answers for well designed and sustainable urban living and could change the way we think about our housing into the future. Having it at the Royal Academy will provoke debate about how architectural innovation might help us meet the UK’s housing needs – for everyone.”